bpf: add a test case to test single tp multiple bpf attachment

The bpf sample program syscall_tp is modified to
show attachment of more than bpf programs
for a particular kernel tracepoint.

Signed-off-by: Yonghong Song <yhs@fb.com>
Acked-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Martin KaFai Lau <kafai@fb.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 53 insertions, 13 deletions

diff --git a/samples/bpf/syscall_tp_user.c b/samples/bpf/syscall_tp_user.c
index a3cb91ebf4e7..9169d3207f18 100644
--- a/samples/bpf/syscall_tp_user.c
+++ b/samples/bpf/syscall_tp_user.c
@@ -23,6 +23,13 @@
  * This requires kernel CONFIG_FTRACE_SYSCALLS to be set.
  */
 
+static void usage(const char *cmd)
+{
+        printf("USAGE: %s [-i num_progs] [-h]\n", cmd);
+        printf("       -i num_progs      # number of progs of the test\n");
+        printf("       -h                # help\n");
+}
+
 static void verify_map(int map_id)
 {
         __u32 key = 0;
@@ -32,22 +39,29 @@ static void verify_map(int map_id)
                 fprintf(stderr, "map_lookup failed: %s\n", strerror(errno));
                 return;
         }
-        if (val == 0)
+        if (val == 0) {
                 fprintf(stderr, "failed: map #%d returns value 0\n", map_id);
+                return;
+        }
+        val = 0;
+        if (bpf_map_update_elem(map_id, &key, &val, BPF_ANY) != 0) {
+                fprintf(stderr, "map_update failed: %s\n", strerror(errno));
+                return;
+        }
 }
 
-int main(int argc, char **argv)
+static int test(char *filename, int num_progs)
 {
-        struct rlimit r = {RLIM_INFINITY, RLIM_INFINITY};
-        char filename[256];
-        int fd;
+        int i, fd, map0_fds[num_progs], map1_fds[num_progs];
 
-        setrlimit(RLIMIT_MEMLOCK, &r);
-        snprintf(filename, sizeof(filename), "%s_kern.o", argv[0]);
-
-        if (load_bpf_file(filename)) {
-                fprintf(stderr, "%s", bpf_log_buf);
-                return 1;
+        for (i = 0; i < num_progs; i++) {
+                if (load_bpf_file(filename)) {
+                        fprintf(stderr, "%s", bpf_log_buf);
+                        return 1;
+                }
+                printf("prog #%d: map ids %d %d\n", i, map_fd[0], map_fd[1]);
+                map0_fds[i] = map_fd[0];
+                map1_fds[i] = map_fd[1];
         }
 
         /* current load_bpf_file has perf_event_open default pid = -1
@@ -64,8 +78,34 @@ int main(int argc, char **argv)
         close(fd);
 
         /* verify the map */
-        verify_map(map_fd[0]);
-        verify_map(map_fd[1]);
+        for (i = 0; i < num_progs; i++) {
+                verify_map(map0_fds[i]);
+                verify_map(map1_fds[i]);
+        }
 
         return 0;
 }
+
+int main(int argc, char **argv)
+{
+        struct rlimit r = {RLIM_INFINITY, RLIM_INFINITY};
+        int opt, num_progs = 1;
+        char filename[256];
+
+        while ((opt = getopt(argc, argv, "i:h")) != -1) {
+                switch (opt) {
+                case 'i':
+                        num_progs = atoi(optarg);
+                        break;
+                case 'h':
+                default:
+                        usage(argv[0]);
+                        return 0;
+                }
+        }
+
+        setrlimit(RLIMIT_MEMLOCK, &r);
+        snprintf(filename, sizeof(filename), "%s_kern.o", argv[0]);
+
+        return test(filename, num_progs);
+}